3 Answers
3

Assuming that you are a Flex developer, already familiar with and working with the source code, and using the latest version (currently 2.3.1). The relevant file is widgets/SearchWidget/SearchResultItemRenderer.mxml and at the bottom of that file is where the source property is set to a specific image (w_link.png):

It looks as though you are using the flex sample viewer.
And talking about the search results tab/button on that widget.
If that is true you would need either the adobe Flashbuilder, or another product to "rebuild" the swf.
There are some open source solutions to this task.
BTW: the infopopupwidget handles the popups when you select an object from the search. The C:\Inetpub\wwwroot\flexviewer\widgets\Search\searchWidget.swf handles the actual search popup.
BTW2: I don't get the red arrow in my 2.3.1 viewer.
search results screenshot here -